The reason I suspect Tomcat at this point is when the app is not under load (i.e. using Jmeter to simulate 10-20 user concurrent load) the app seems OK. the response times are acceptable even under as long as a servlet doesn't retrieve a lot of data. (I didn't write the app, just trying to fix it). The app is running fairly well under JDK 1.17 on Java WebServer on NT but falls on its knees under JDK 1.3.0 and Tomcat 4.1.18.
We have done a bunch of other things on Tomcat (not 4.1.18) without having this kind of behavior.
Dov Rosenberg
On Wednesday, March 5, 2003, at 04:10 PM, Shapira, Yoav wrote:
Howdy,
Given
"once a servlet
loads that retrieves a bunch of data, the CPU processing starts to
increase until it pegs at 99% (according to TOP). All users then stop
responding. The only way to recover is to terminate the process and
restart Tomcat. The garbage collection indicates when the app becomes
unresponsive the garbage collection shows a lot of full garbage
collection cycles but the app never recovers - it essentially goes into
an endless loop."
what makes you think this is a tomcat problem, as opposed to for example
a loop in your app or a memory leak in your app?
Yoav Shapira Millennium ChemInformatics
web.xml.-----Original Message----- From: Dov Rosenberg [mailto:[EMAIL PROTECTED] Sent: Wednesday, March 05, 2003 3:57 PM To: [EMAIL PROTECTED] Subject: Tomcat 4.1.18: 500+ Servlets locks up on Solaris under load
I have a Solaris server running Tomcat 4.1.18 and Java 1.3.0 with a
single CPU and 2GIG RAM. The application has 500+ servlets that were
originally developed under JDK 1.17b to run under the old Java Web
Server on Windows NT4. The old system seems to handle the load much
better than the new version. We have configured the Invoker to load the
servlets automatically instead of explicitly naming them in the
I am launching the Tomcat server with the following parameters:
-server -Xms384m -Xmx384m -XX:NewSize=128m -XX:MaxNewSize=128m -Xconcurrentio -Xincgc -verbose:gc
under load the Tomcat server runs fine for a bit but once a servlet
loads that retrieves a bunch of data, the CPU processing starts to
increase until it pegs at 99% (according to TOP). All users then stop
responding. The only way to recover is to terminate the process and
restart Tomcat. The garbage collection indicates when the app becomes
unresponsive the garbage collection shows a lot of full garbage
collection cycles but the app never recovers - it essentially goes into
an endless loop.
Some of the parameters in our server.xml are:
<Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
redirectPort="443" bufferSize="2048" port="8009" connectionTimeout="0"
scheme="http" enableLookups="true" secure="false"
protocolHandlerClassName="org.apache.jk.server.JkCoyoteHandler"
debug="9" disableUploadTimeout="false" ProxyPort="0" maxProcessors="75"
minProcessors="5" tcpNoDelay="true" acceptCount="10"
useURIValidationHack="false">
<Factory
className="org.apache.catalina.net.DefaultServerSocketFactory"/>
</Connector>
<Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
redirectPort="-1" bufferSize="2048" port="80" connectionTimeout="0"
scheme="http" enableLookups="true" secure="false"
protocolHandlerClassName="org.apache.coyote.http11.Http11Protocol"
debug="9" disable UploadTimeout="false" proxyPort="0"
maxProcessors="-1" minProcessors="5" tcpNoDelay="true" acceptCount="10"
useURIValidationHack="true">
<Factory
className="org.apache.catalina.net.DefaultServerSocketFactory"/>
</Connector>
I am running Tomcat on port 80 as the root user if that has any bearing
on things. Originally we had Apache in the mix, but to simplify
figuring out the problems we have configured Tomcat to act as the web
server for the time being. Some of the static resource directories are
symbolic links.
Dov Rosenberg Conviveon Corporation 407-339-1177 ext 102
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